vt: new filesystem using tevd

.idea/markdown-navigator.xml

@@ -0,0 +1,70 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="MarkdownProjectSettings">
+    <PreviewSettings splitEditorLayout="SPLIT" splitEditorPreview="PREVIEW" useGrayscaleRendering="false" zoomFactor="1.0" maxImageWidth="0" showGitHubPageIfSynced="false" allowBrowsingInPreview="false" synchronizePreviewPosition="true" highlightPreviewType="NONE" highlightFadeOut="5" highlightOnTyping="true" synchronizeSourcePosition="true" verticallyAlignSourceAndPreviewSyncPosition="true" showSearchHighlightsInPreview="false" showSelectionInPreview="true">
+      <PanelProvider>
+        <provider providerId="com.vladsch.idea.multimarkdown.editor.swing.html.panel" providerName="Default - Swing" />
+      </PanelProvider>
+    </PreviewSettings>
+    <ParserSettings>
+      <PegdownExtensions>
+        <option name="ABBREVIATIONS" value="false" />
+        <option name="ANCHORLINKS" value="true" />
+        <option name="ASIDE" value="false" />
+        <option name="ATXHEADERSPACE" value="true" />
+        <option name="AUTOLINKS" value="true" />
+        <option name="DEFINITIONS" value="false" />
+        <option name="FENCED_CODE_BLOCKS" value="true" />
+        <option name="FOOTNOTES" value="false" />
+        <option name="HARDWRAPS" value="false" />
+        <option name="INSERTED" value="false" />
+        <option name="QUOTES" value="false" />
+        <option name="RELAXEDHRULES" value="true" />
+        <option name="SMARTS" value="false" />
+        <option name="STRIKETHROUGH" value="true" />
+        <option name="SUBSCRIPT" value="false" />
+        <option name="SUPERSCRIPT" value="false" />
+        <option name="SUPPRESS_HTML_BLOCKS" value="false" />
+        <option name="SUPPRESS_INLINE_HTML" value="false" />
+        <option name="TABLES" value="true" />
+        <option name="TASKLISTITEMS" value="true" />
+        <option name="TOC" value="false" />
+        <option name="WIKILINKS" value="true" />
+      </PegdownExtensions>
+      <ParserOptions>
+        <option name="COMMONMARK_LISTS" value="false" />
+        <option name="DUMMY" value="false" />
+        <option name="EMOJI_SHORTCUTS" value="true" />
+        <option name="FLEXMARK_FRONT_MATTER" value="false" />
+        <option name="GFM_LOOSE_BLANK_LINE_AFTER_ITEM_PARA" value="true" />
+        <option name="GFM_TABLE_RENDERING" value="true" />
+        <option name="GITBOOK_URL_ENCODING" value="false" />
+        <option name="GITHUB_EMOJI_URL" value="false" />
+        <option name="GITHUB_LISTS" value="true" />
+        <option name="GITHUB_WIKI_LINKS" value="true" />
+        <option name="JEKYLL_FRONT_MATTER" value="false" />
+        <option name="SIM_TOC_BLANK_LINE_SPACER" value="true" />
+      </ParserOptions>
+    </ParserSettings>
+    <HtmlSettings headerTopEnabled="false" headerBottomEnabled="false" bodyTopEnabled="false" bodyBottomEnabled="false" embedUrlContent="false" addPageHeader="true">
+      <GeneratorProvider>
+        <provider providerId="com.vladsch.idea.multimarkdown.editor.swing.html.generator" providerName="Default Swing HTML Generator" />
+      </GeneratorProvider>
+      <headerTop />
+      <headerBottom />
+      <bodyTop />
+      <bodyBottom />
+    </HtmlSettings>
+    <CssSettings previewScheme="UI_SCHEME" cssUri="" isCssUriEnabled="false" isCssTextEnabled="false" isDynamicPageWidth="true">
+      <StylesheetProvider>
+        <provider providerId="com.vladsch.idea.multimarkdown.editor.swing.html.css" providerName="Default Swing Stylesheet" />
+      </StylesheetProvider>
+      <ScriptProviders />
+      <cssText />
+    </CssSettings>
+    <HtmlExportSettings updateOnSave="false" parentDir="$ProjectFileDir$" targetDir="$ProjectFileDir$" cssDir="" scriptDir="" plainHtml="false" imageDir="" copyLinkedImages="false" imageUniquifyType="0" targetExt="" useTargetExt="false" noCssNoScripts="false" linkToExportedHtml="true" exportOnSettingsChange="true" regenerateOnProjectOpen="false" />
+    <LinkMapSettings>
+      <textMaps />
+    </LinkMapSettings>
+  </component>
+</project>

.idea/markdown-navigator/profiles_settings.xml

@@ -0,0 +1,3 @@
+<component name="MarkdownNavigator.ProfileManager">
+  <settings default="" pdf-export="" />
+</component>

src/net/torvald/terrarum/StateVTTest.kt

@@ -21,7 +21,7 @@ class StateVTTest : BasicGameState() {
 
     // HiRes: 100x64, LoRes: 80x25
     val computerInside = TerrarumComputer(peripheralSlots = 8)
-    val vt = SimpleTextTerminal(SimpleTextTerminal.AMBER, 80, 25,
+    val vt = SimpleTextTerminal(SimpleTextTerminal.BLUE_NOVELTY, 80, 25,
             computerInside, colour = false, hires = false)
 
 

src/net/torvald/terrarum/Terrarum.kt

@@ -189,7 +189,7 @@ object Terrarum : StateBasedGame(GAME_NAME) {
      *
      * e.g. 0x02010034 can be translated as 2.1.52
      */
-    const val VERSION_RAW = 0x000200E1
+    const val VERSION_RAW = 0x0002018E
     const val VERSION_STRING: String =
             "${VERSION_RAW.ushr(24)}.${VERSION_RAW.and(0xFF0000).ushr(16)}.${VERSION_RAW.and(0xFFFF)}"
     const val NAME = "Terrarum"
@@ -303,7 +303,7 @@ object Terrarum : StateBasedGame(GAME_NAME) {
 
         gc.graphics.clear() // clean up any 'dust' in the buffer
 
-        addState(StateVTTest())
+        //addState(StateVTTest())
         //addState(StateGraphicComputerTest())
         //addState(StateTestingLightning())
         //addState(StateSplash())
@@ -318,7 +318,7 @@ object Terrarum : StateBasedGame(GAME_NAME) {
         //addState(StateMidiInputTest())
         //addState(StateNewRunesTest())
 
-        //ingame = StateInGame(); addState(ingame)
+        ingame = StateInGame(); addState(ingame)
 
 
         // foolproof
@@ -650,4 +650,6 @@ operator fun Color.minus(other: Color) = Color(
     this.a - other.a
 )
 
-fun Int.toHex() = Integer.toHexString(this)
+fun Int.toHex() = this.toString(16)
+
+

src/net/torvald/terrarum/debuggerapp/ActorValueTracker.kt

@@ -9,6 +9,7 @@ import net.torvald.terrarum.gameactors.ActorWithSprite
 import net.torvald.terrarum.mapdrawer.FeaturesDrawer
 import java.awt.BorderLayout
 import java.awt.GridLayout
+import java.awt.event.MouseAdapter
 import java.awt.event.MouseEvent
 import java.awt.event.MouseListener
 import javax.swing.*
@@ -58,11 +59,7 @@ class ActorValueTracker constructor() : JFrame() {
         }
 
         // button listener for buttons
-        buttonAddAV.addMouseListener(object : MouseListener {
+        buttonAddAV.addMouseListener(object : MouseAdapter() {
-            override fun mouseEntered(e: MouseEvent?) { }
-            override fun mouseClicked(e: MouseEvent?) { }
-            override fun mouseReleased(e: MouseEvent?) { }
-            override fun mouseExited(e: MouseEvent?) { }
             override fun mousePressed(e: MouseEvent?) {
                 if (actor != null && modavInputKey.text.isNotBlank() && modavInputValue.text.isNotBlank()) {
                     SetAV.execute((
@@ -74,11 +71,7 @@ class ActorValueTracker constructor() : JFrame() {
                 }
             }
         })
-        buttonDelAV.addMouseListener(object : MouseListener {
+        buttonDelAV.addMouseListener(object : MouseAdapter() {
-            override fun mouseEntered(e: MouseEvent?) { }
-            override fun mouseClicked(e: MouseEvent?) { }
-            override fun mouseReleased(e: MouseEvent?) { }
-            override fun mouseExited(e: MouseEvent?) { }
             override fun mousePressed(e: MouseEvent?) {
                 if (actorValue != null && modavInputKey.text.isNotBlank()) {
                     actorValue!!.remove(modavInputKey.text)
@@ -87,11 +80,7 @@ class ActorValueTracker constructor() : JFrame() {
                 }
             }
         })
-        buttonChangeActor.addMouseListener(object : MouseListener {
+        buttonChangeActor.addMouseListener(object : MouseAdapter() {
-            override fun mouseEntered(e: MouseEvent?) { }
-            override fun mouseClicked(e: MouseEvent?) { }
-            override fun mouseReleased(e: MouseEvent?) { }
-            override fun mouseExited(e: MouseEvent?) { }
             override fun mousePressed(e: MouseEvent?) {
                 if (actorIDField.text.toLowerCase() == "player") {
                     actor = Terrarum.ingame!!.player

src/net/torvald/terrarum/gameactors/ActorInventory.kt

@@ -121,29 +121,17 @@ class ActorInventory() {
         return capacityMode
     }
 
-    fun getTotalWeight(): Double {
+    fun getTotalWeight(): Double = itemList.map { it.item.mass * it.amount }.sum()
-        var weight = 0.0
-        itemList.forEach { weight += it.item.mass * it.amount }
-
-        return weight
-    }
 
     /**
      * Real amount
      */
-    fun getTotalCount(): Int {
+    fun getTotalCount(): Int = itemList.map { it.amount }.sum()
-        var count = 0
-        itemList.forEach { count += it.amount }
-
-        return count
-    }
 
     /**
      * Unique amount, multiple items are calculated as one
      */
-    fun getTotalUniqueCount(): Int {
+    fun getTotalUniqueCount(): Int = itemList.size
-        return itemList.size
-    }
 
     /**
      * Check whether the itemList contains too many items

src/net/torvald/terrarum/gameactors/DecodeTapestry.kt

@@ -111,19 +111,15 @@ object DecodeTapestry {
     val FORMAT_64 = 2
 
     operator fun invoke(fileObj: File): TapestryObject {
-        fun magicMismatch(magic: ByteArray): Boolean {
+        fun magicMismatch(magic: ByteArray, array: ByteArray): Boolean {
-            MAGIC.forEachIndexed { i, byte ->
+            return !Arrays.equals(array.sliceArray(0..magic.lastIndex), magic)
-                if (byte != magic[i])
-                    return true
-            }
-            return false
         }
 
         val file = fileObj.readBytes()
 
         val magic = file.copyOfRange(0, 4)
 
-        if (magicMismatch(magic))
+        if (magicMismatch(MAGIC, magic))
             throw RuntimeException("Invalid file --  type mismatch: expected header " +
                                    "${MAGIC[0]} ${MAGIC[1]} ${MAGIC[2]} ${MAGIC[3]}; got " +
                                    "${magic[0]} ${magic[1]} ${magic[2]} ${magic[3]}")
@@ -156,8 +152,8 @@ object DecodeTapestry {
 
 
 
-        val artName = kotlin.text.String(artNameBytes.toByteArray(), charset = Charset.forName("UTF-8"))
+        val artName = String(artNameBytes.toByteArray(), charset = Charset.forName("UTF-8"))
-        val authorName = kotlin.text.String(authorNameBytes.toByteArray(), charset = Charset.forName("UTF-8"))
+        val authorName = String(authorNameBytes.toByteArray(), charset = Charset.forName("UTF-8"))
 
         val imageDataSize = file.size - readCounter
         val height = imageDataSize / width

src/net/torvald/terrarum/virtualcomputer/assets/lua/BOOT.lua

@@ -1015,8 +1015,6 @@ sandbox._G = sandbox
 -- path for any ingame libraries
 package.path = "/net/torvald/terrarum/virtualcomputer/assets/lua/?.lua;" .. package.path
 
-_G.__scanMode__ = "UNINIT" -- part of inputstream implementation
-
 local screenbufferdim = term.width() * term.height()
 local screencolours = 4
 if term.isCol() then screencolours = 8
@@ -1027,7 +1025,7 @@ if not computer.prompt then computer.prompt = DC3.."> "..DC4 end
 if not computer.verbose then computer.verbose = true end -- print debug info
 if not computer.loadedCLayer then computer.loadedCLayer = {} end -- list of loaded compatibility layers
 -- if no bootloader is pre-defined via EFI, use default one
-if not computer.bootloader then computer.bootloader = "/boot/efi" end
+if not computer.bootloader then computer.bootloader = "boot/efi" end
 if not computer.OEM then computer.OEM = "" end
 machine.totalMemory = _G.totalMemory
 if not computer.bellpitch then computer.bellpitch = 950 end

src/net/torvald/terrarum/virtualcomputer/computer/TerrarumComputer.kt

@@ -9,10 +9,13 @@ import org.luaj.vm2.lib.ZeroArgFunction
 import org.luaj.vm2.lib.jse.JsePlatform
 import net.torvald.terrarum.KVHashMap
 import net.torvald.terrarum.Millisec
+import net.torvald.terrarum.Terrarum
 import net.torvald.terrarum.gameactors.roundInt
 import net.torvald.terrarum.virtualcomputer.luaapi.*
 import net.torvald.terrarum.virtualcomputer.peripheral.*
 import net.torvald.terrarum.virtualcomputer.terminal.*
+import net.torvald.terrarum.virtualcomputer.tvd.VDUtil
+import net.torvald.terrarum.virtualcomputer.tvd.VirtualDisk
 import net.torvald.terrarum.virtualcomputer.worldobject.ComputerPartsCodex
 import org.lwjgl.BufferUtils
 import org.lwjgl.openal.AL
@@ -22,6 +25,8 @@ import org.newdawn.slick.Input
 import java.io.*
 import java.nio.ByteBuffer
 import java.util.*
+import java.util.logging.Level
+import kotlin.collections.HashMap
 
 /**
  * A part that makes "computer fixture" actually work
@@ -87,6 +92,26 @@ class TerrarumComputer(peripheralSlots: Int) {
     val milliTime: Int
         get() = (System.currentTimeMillis() - startupTimestamp).toInt()
 
+    /** String:
+     *    if it's UUID, formatted UUID as string, always 36 chars
+     *    if not (test purpose only!), just String
+     */
+    val diskRack = HashMap<String, VirtualDisk>()
+
+    fun attachDisk(slot: String, filename: String) {
+        computerValue[slot] = filename
+
+        // put disk in diskRack
+        if (filename.isNotEmpty() && filename.isNotBlank()) {
+            diskRack[slot] = VDUtil.readDiskArchive(
+                    File(Terrarum.currentSaveDir.path + "/computers/$filename").absoluteFile,
+                    Level.WARNING,
+                    { },
+                    Filesystem.sysCharset
+            )
+        }
+    }
+
     init {
         computerValue["memslot0"] = 4864 // -1 indicates mem slot is empty
         computerValue["memslot1"] = -1 // put index of item here
@@ -96,20 +121,20 @@ class TerrarumComputer(peripheralSlots: Int) {
         computerValue["processor"] = -1 // do.
 
         // as in "dev/hda"; refers hard disk drive (and no partitioning)
-        computerValue["hda"] = "uuid_testhda" // 'UUID rendered as String' or "none"
+        attachDisk("hda", "uuid_testhda")
-        computerValue["hdb"] = "uuid_testhdb"
+        attachDisk("hdb", "")
-        computerValue["hdc"] = "none"
+        attachDisk("hdc", "")
-        computerValue["hdd"] = "none"
+        attachDisk("hdd", "")
         // as in "dev/fd1"; refers floppy disk drive
-        computerValue["fd1"] = "uuid_testfd1"
+        attachDisk("fd1", "")
-        computerValue["fd2"] = "none"
+        attachDisk("fd2", "")
-        computerValue["fd3"] = "none"
+        attachDisk("fd3", "")
-        computerValue["fd4"] = "none"
+        attachDisk("fd4", "")
         // SCSI connected optical drive
-        computerValue["sda"] = "none"
+        attachDisk("sda", "")
 
         // boot device
-        computerValue["boot"] = computerValue.getAsString("hda")!!
+        computerValue["boot"] = "hda"
     }
 
     fun getPeripheral(tableName: String): Peripheral? {
@@ -168,7 +193,6 @@ class TerrarumComputer(peripheralSlots: Int) {
         PcSpeakerDriver(luaJ_globals, this)
         WorldInformationProvider(luaJ_globals)
 
-
         // secure the sandbox
         //luaJ_globals["io"] = LuaValue.NIL
         // dubug should be sandboxed in BOOT.lua (use OpenComputers code)

src/net/torvald/terrarum/virtualcomputer/luaapi/FilesystemDir.kt

@@ -0,0 +1,522 @@
+package net.torvald.terrarum.virtualcomputer.luaapi
+
+import org.luaj.vm2.*
+import org.luaj.vm2.lib.OneArgFunction
+import org.luaj.vm2.lib.TwoArgFunction
+import org.luaj.vm2.lib.ZeroArgFunction
+import net.torvald.terrarum.Terrarum
+import net.torvald.terrarum.toHex
+import net.torvald.terrarum.virtualcomputer.computer.TerrarumComputer
+import net.torvald.terrarum.virtualcomputer.luaapi.Term.Companion.checkIBM437
+import java.io.*
+import java.nio.file.Files
+import java.nio.file.NoSuchFileException
+import java.nio.file.Path
+import java.nio.file.Paths
+import java.util.*
+
+/**
+ * computer directory:
+ * .../computers/
+ *      media/hda/  ->  .../computers/<uuid for the hda>/
+ * 
+ * Created by minjaesong on 16-09-17.
+ *
+ *
+ * NOTES:
+ *      Don't convert '\' to '/'! Rev-slash is used for escape character in sh, and we're sh-compatible!
+ *      Use .absoluteFile whenever possible; there's fuckin oddity! (http://bugs.java.com/bugdatabase/view_bug.do;:YfiG?bug_id=4483097)
+ */
+@Deprecated("Fuck permission and shit, we go virtual. Use FilesystemTar")
+internal class FilesystemDir(globals: Globals, computer: TerrarumComputer) {
+
+    init {
+        // load things. WARNING: THIS IS MANUAL!
+        globals["fs"] = LuaValue.tableOf()
+        globals["fs"]["list"] = ListFiles(computer) // CC compliant
+        globals["fs"]["exists"] = FileExists(computer) // CC/OC compliant
+        globals["fs"]["isDir"] = IsDirectory(computer) // CC compliant
+        globals["fs"]["isFile"] = IsFile(computer)
+        globals["fs"]["isReadOnly"] = IsReadOnly(computer) // CC compliant
+        globals["fs"]["getSize"] = GetSize(computer) // CC compliant
+        globals["fs"]["mkdir"] = Mkdir(computer)
+        globals["fs"]["mv"] = Mv(computer)
+        globals["fs"]["cp"] = Cp(computer)
+        globals["fs"]["rm"] = Rm(computer)
+        globals["fs"]["concat"] = ConcatPath(computer) // OC compliant
+        globals["fs"]["open"] = OpenFile(computer) //CC compliant
+        globals["fs"]["parent"] = GetParentDir(computer)
+        // fs.dofile defined in BOOT
+        // fs.fetchText defined in ROMLIB
+    }
+
+    companion object {
+        fun ensurePathSanity(path: LuaValue) {
+            if (path.checkIBM437().contains(Regex("""\.\.""")))
+                throw LuaError("'..' on path is not supported.")
+            if (!isValidFilename(path.checkIBM437()))
+                throw IOException("path contains invalid characters")
+        }
+
+        var isCaseInsensitive: Boolean
+
+        init {
+            try {
+                val uuid = UUID.randomUUID().toString()
+                val lowerCase = File(Terrarum.currentSaveDir, uuid + "oc_rox")
+                val upperCase = File(Terrarum.currentSaveDir, uuid + "OC_ROX")
+                // This should NEVER happen but could also lead to VERY weird bugs, so we
+                // make sure the files don't exist.
+                if (lowerCase.exists()) lowerCase.delete()
+                if (upperCase.exists()) upperCase.delete()
+
+                lowerCase.createNewFile()
+
+                val insensitive = upperCase.exists()
+                lowerCase.delete()
+
+                isCaseInsensitive = insensitive
+
+                println("[Filesystem] Case insensitivity: $isCaseInsensitive")
+            }
+            catch (e: IOException) {
+                System.err.println("[Filesystem] Couldn't determine if the file system is case sensitive, falling back to insensitive.")
+                e.printStackTrace(System.out)
+                isCaseInsensitive = true
+            }
+        }
+
+        // Worst-case: we're on Windows or using a FAT32 partition mounted in *nix.
+        // Note: we allow / as the path separator and expect all \s to be converted
+        // accordingly before the path is passed to the file system.
+        private val invalidChars = Regex("""[<>:"|?*\u0000-\u001F]""") // original OC uses Set(); we use regex
+
+        fun isValidFilename(name: String) = !name.contains(invalidChars)
+
+        fun String.validatePath() : String {
+            if (!isValidFilename(this)) {
+                throw IOException("path contains invalid characters")
+            }
+            return this
+        }
+
+        /** actual directory: <appdata>/Saves/<savename>/computers/<drivename>/
+         * directs media/ directory to /<uuid> directory
+         */
+        fun TerrarumComputer.getRealPath(luapath: LuaValue) : String {
+            // direct mounted paths to real path
+            val computerDir = Terrarum.currentSaveDir.absolutePath + "/computers/"
+            /* if not begins with "(/?)media/", direct to boot
+             * else, to corresponding drives
+             * 
+             * List of device names (these are auto-mounted. why? primitivism :p):
+             * = hda - hdd: hard disks
+             * = fd1 - fd4: floppy drives
+             * = sda: whatever external drives, usually a CD
+             * = boot: current boot device
+             */
+            
+            // remove first '/' in path
+            var path = luapath.checkIBM437().validatePath()
+            if (path.startsWith('/')) path = path.substring(1)
+
+            val finalPath: String
+
+            if (path.startsWith("media/")) {
+                val device = path.substring(6, 9)
+                val subPath = path.substring(9)
+                finalPath = computerDir + this.computerValue.getAsString("device") + subPath
+            }
+            else {
+                finalPath = computerDir + this.computerValue.getAsString("boot") + "/" + path
+            }
+
+            // remove trailing slash
+            return if (finalPath.endsWith("\\") || finalPath.endsWith("/"))
+                finalPath.substring(0, finalPath.length - 1)
+            else
+                finalPath
+        }
+
+        fun combinePath(base: String, local: String) : String {
+            return "$base$local".replace("//", "/")
+        }
+    }
+
+    /**
+     * @param cname == UUID of the drive
+     *
+     * actual directory: <appdata>/Saves/<savename>/computers/<drivename>/
+     */
+    class ListFiles(val computer: TerrarumComputer) : OneArgFunction() {
+        override fun call(path: LuaValue) : LuaValue {
+            FilesystemDir.ensurePathSanity(path)
+
+            println("ListFiles: got path ${path.checkIBM437()}")
+
+            val table = LuaTable()
+            val file = File(computer.getRealPath(path)).absoluteFile
+            try {
+                file.list().forEachIndexed { i, s -> table.insert(i, LuaValue.valueOf(s)) }
+            }
+            catch (e: NullPointerException) {}
+            return table
+        }
+    }
+
+    /** Don't use this. Use isFile */
+    class FileExists(val computer: TerrarumComputer) : OneArgFunction() {
+        override fun call(path: LuaValue) : LuaValue {
+            FilesystemDir.ensurePathSanity(path)
+
+            return LuaValue.valueOf(Files.exists(Paths.get(computer.getRealPath(path)).toAbsolutePath()))
+        }
+    }
+
+    class IsDirectory(val computer: TerrarumComputer) : OneArgFunction() {
+        override fun call(path: LuaValue) : LuaValue {
+            FilesystemDir.ensurePathSanity(path)
+
+            val isDir = Files.isDirectory(Paths.get(computer.getRealPath(path)).toAbsolutePath())
+            val exists = Files.exists(Paths.get(computer.getRealPath(path)).toAbsolutePath())
+
+            return LuaValue.valueOf(isDir || exists)
+        }
+    }
+
+    class IsFile(val computer: TerrarumComputer) : OneArgFunction() {
+        override fun call(path: LuaValue) : LuaValue {
+            FilesystemDir.ensurePathSanity(path)
+
+            // check if the path is file by checking:
+            // 1. isfile
+            // 2. canwrite
+            // 3. length
+            // Why? Our Java simply wants to fuck you.
+
+            val path = Paths.get(computer.getRealPath(path)).toAbsolutePath()
+            var result = false
+            result = Files.isRegularFile(path)
+
+            if (!result) result = Files.isWritable(path)
+
+            if (!result)
+                try { result = Files.size(path) > 0 }
+                catch (e: NoSuchFileException) { result = false }
+
+            return LuaValue.valueOf(result)
+        }
+    }
+
+    class IsReadOnly(val computer: TerrarumComputer) : OneArgFunction() {
+        override fun call(path: LuaValue) : LuaValue {
+            FilesystemDir.ensurePathSanity(path)
+
+            return LuaValue.valueOf(!Files.isWritable(Paths.get(computer.getRealPath(path)).toAbsolutePath()))
+        }
+    }
+
+    /** we have 4GB file size limit */
+    class GetSize(val computer: TerrarumComputer) : OneArgFunction() {
+        override fun call(path: LuaValue) : LuaValue {
+            FilesystemDir.ensurePathSanity(path)
+
+            return LuaValue.valueOf(Files.size(Paths.get(computer.getRealPath(path)).toAbsolutePath()).toInt())
+        }
+    }
+
+    // TODO class GetFreeSpace
+
+    /**
+     * difference with ComputerCraft: it returns boolean, true on successful.
+     */
+    class Mkdir(val computer: TerrarumComputer) : OneArgFunction() {
+        override fun call(path: LuaValue) : LuaValue {
+            FilesystemDir.ensurePathSanity(path)
+
+            return LuaValue.valueOf(File(computer.getRealPath(path)).absoluteFile.mkdir())
+        }
+    }
+
+    /**
+     * moves a directory, overwrites the target
+     */
+    class Mv(val computer: TerrarumComputer) : TwoArgFunction() {
+        override fun call(from: LuaValue, to: LuaValue) : LuaValue {
+            FilesystemDir.ensurePathSanity(from)
+            FilesystemDir.ensurePathSanity(to)
+
+            val fromFile = File(computer.getRealPath(from)).absoluteFile
+            var success = fromFile.copyRecursively(
+                    File(computer.getRealPath(to)).absoluteFile, overwrite = true
+            )
+            if (success) success = fromFile.deleteRecursively()
+            else return LuaValue.valueOf(false)
+            return LuaValue.valueOf(success)
+        }
+    }
+
+    /**
+     * copies a directory, overwrites the target
+     * difference with ComputerCraft: it returns boolean, true on successful.
+     */
+    class Cp(val computer: TerrarumComputer) : TwoArgFunction() {
+        override fun call(from: LuaValue, to: LuaValue) : LuaValue {
+            FilesystemDir.ensurePathSanity(from)
+            FilesystemDir.ensurePathSanity(to)
+
+            return LuaValue.valueOf(
+                    File(computer.getRealPath(from)).absoluteFile.copyRecursively(
+                            File(computer.getRealPath(to)).absoluteFile, overwrite = true
+                    )
+            )
+        }
+    }
+
+    /**
+     * difference with ComputerCraft: it returns boolean, true on successful.
+     */
+    class Rm(val computer: TerrarumComputer) : OneArgFunction() {
+        override fun call(path: LuaValue) : LuaValue {
+            FilesystemDir.ensurePathSanity(path)
+
+            return LuaValue.valueOf(
+                    File(computer.getRealPath(path)).absoluteFile.deleteRecursively()
+            )
+        }
+    }
+
+    class ConcatPath(val computer: TerrarumComputer) : TwoArgFunction() {
+        override fun call(base: LuaValue, local: LuaValue) : LuaValue {
+            FilesystemDir.ensurePathSanity(base)
+            FilesystemDir.ensurePathSanity(local)
+
+            val combinedPath = combinePath(base.checkIBM437().validatePath(), local.checkIBM437().validatePath())
+            return LuaValue.valueOf(combinedPath)
+        }
+    }
+
+    /**
+     * @param mode: r, rb, w, wb, a, ab
+     *
+     * Difference: TEXT MODE assumes CP437 instead of UTF-8!
+     *
+     * When you have opened a file you must always close the file handle, or else data may not be saved.
+     *
+     * FILE class in CC:
+     * (when you look thru them using file = fs.open("./test", "w")
+     *
+     * file = {
+     *      close = function()
+     *      -- write mode
+     *      write = function(string)
+     *      flush = function() -- write, keep the handle
+     *      writeLine = function(string) -- text mode
+     *      -- read mode
+     *      readLine = function() -- text mode
+     *      readAll = function()
+     *      -- binary read mode
+     *      read = function() -- read single byte. return: number or nil
+     *      -- binary write mode
+     *      write = function(byte)
+     *      writeBytes = function(string as bytearray)
+     * }
+     */
+    class OpenFile(val computer: TerrarumComputer) : TwoArgFunction() {
+        override fun call(path: LuaValue, mode: LuaValue) : LuaValue {
+            FilesystemDir.ensurePathSanity(path)
+
+            
+
+            val mode = mode.checkIBM437().toLowerCase()
+            val luaClass = LuaTable()
+            val file = File(computer.getRealPath(path)).absoluteFile
+
+            if (mode.contains(Regex("""[aw]""")) && !file.canWrite())
+                throw LuaError("Cannot open file for " +
+                               "${if (mode.startsWith('w')) "read" else "append"} mode" +
+                               ": is readonly.")
+
+
+
+
+            when (mode) {
+                "r"  -> {
+                    try {
+                        val fr = FileReader(file)
+                        luaClass["close"] = FileClassClose(fr)
+                        luaClass["readLine"] = FileClassReadLine(fr)
+                        luaClass["readAll"] = FileClassReadAll(file.toPath())
+                    }
+                    catch (e: FileNotFoundException) {
+                        e.printStackTrace()
+                        throw LuaError(
+                                if (e.message != null && e.message!!.contains(Regex("""[Aa]ccess (is )?denied""")))
+                                    "$path: access denied."
+                                else
+                                    "$path: no such file."
+                        )
+                    }
+                }
+                "rb" -> {
+                    try {
+                        val fis = FileInputStream(file)
+                        luaClass["close"] = FileClassClose(fis)
+                        luaClass["read"] = FileClassReadByte(fis)
+                        luaClass["readAll"] = FileClassReadAll(file.toPath())
+                    }
+                    catch (e: FileNotFoundException) {
+                        e.printStackTrace()
+                        throw LuaError("$path: no such file.")
+                    }
+                }
+                "w", "a"  -> {
+                    try {
+                        val fw = FileWriter(file, (mode.startsWith('a')))
+                        luaClass["close"] = FileClassClose(fw)
+                        luaClass["write"] = FileClassPrintText(fw)
+                        luaClass["writeLine"] = FileClassPrintlnText(fw)
+                        luaClass["flush"] = FileClassFlush(fw)
+                    }
+                    catch (e: FileNotFoundException) {
+                        e.printStackTrace()
+                        throw LuaError("$path: is a directory.")
+                    }
+                }
+                "wb", "ab" -> {
+                    try {
+                        val fos = FileOutputStream(file, (mode.startsWith('a')))
+                        luaClass["close"] = FileClassClose(fos)
+                        luaClass["write"] = FileClassWriteByte(fos)
+                        luaClass["writeBytes"] = FileClassWriteBytes(fos)
+                        luaClass["flush"] = FileClassFlush(fos)
+                    }
+                    catch (e: FileNotFoundException) {
+                        e.printStackTrace()
+                        throw LuaError("$path: is a directory.")
+                    }
+                }
+            }
+
+            return luaClass
+        }
+    }
+
+    class GetParentDir(val computer: TerrarumComputer) : OneArgFunction() {
+        override fun call(path: LuaValue) : LuaValue {
+            FilesystemDir.ensurePathSanity(path)
+
+            var pathSB = StringBuilder(path.checkIBM437())
+
+            // backward travel, drop chars until '/' has encountered
+            while (!pathSB.endsWith('/'))
+                pathSB.deleteCharAt(pathSB.lastIndex - 1)
+
+            // drop trailing '/'
+            if (pathSB.endsWith('/'))
+                pathSB.deleteCharAt(pathSB.lastIndex - 1)
+
+            return LuaValue.valueOf(pathSB.toString())
+        }
+    }
+
+
+    //////////////////////////////
+    // OpenFile implementations //
+    //////////////////////////////
+
+    private class FileClassClose(val fo: Any) : ZeroArgFunction() {
+        override fun call() : LuaValue {
+            if (fo is FileOutputStream)
+                fo.close()
+            else if (fo is FileWriter)
+                fo.close()
+            else if (fo is FileReader)
+                fo.close()
+            else if (fo is FileInputStream)
+                fo.close()
+            else
+                throw IllegalArgumentException("Unacceptable file output: must be either Input/OutputStream or Reader/Writer.")
+
+            return LuaValue.NONE
+        }
+    }
+
+    private class FileClassWriteByte(val fos: FileOutputStream) : OneArgFunction() {
+        override fun call(byte: LuaValue) : LuaValue {
+            fos.write(byte.checkint())
+
+            return LuaValue.NONE
+        }
+    }
+
+    private class FileClassWriteBytes(val fos: FileOutputStream) : OneArgFunction() {
+        override fun call(byteString: LuaValue) : LuaValue {
+            val byteString = byteString.checkIBM437()
+            val bytearr = ByteArray(byteString.length, { byteString[it].toByte() })
+            fos.write(bytearr)
+
+            return LuaValue.NONE
+        }
+    }
+
+    private class FileClassPrintText(val fw: FileWriter) : OneArgFunction() {
+        override fun call(string: LuaValue) : LuaValue {
+            val text = string.checkIBM437()
+            fw.write(text)
+            return LuaValue.NONE
+        }
+    }
+
+    private class FileClassPrintlnText(val fw: FileWriter) : OneArgFunction() {
+        override fun call(string: LuaValue) : LuaValue {
+            val text = string.checkIBM437() + "\n"
+            fw.write(text)
+            return LuaValue.NONE
+        }
+    }
+
+    private class FileClassFlush(val fo: Any) : ZeroArgFunction() {
+        override fun call() : LuaValue {
+            if (fo is FileOutputStream)
+                fo.flush()
+            else if (fo is FileWriter)
+                fo.flush()
+            else
+                throw IllegalArgumentException("Unacceptable file output: must be either OutputStream or Writer.")
+
+            return LuaValue.NONE
+        }
+    }
+
+    private class FileClassReadByte(val fis: FileInputStream) : ZeroArgFunction() {
+        override fun call() : LuaValue {
+            val readByte = fis.read()
+            return if (readByte == -1) LuaValue.NIL else LuaValue.valueOf(readByte)
+        }
+    }
+
+    private class FileClassReadAllBytes(val path: Path) : ZeroArgFunction() {
+        override fun call() : LuaValue {
+            val byteArr = Files.readAllBytes(path)
+            val s: String = java.lang.String(byteArr, "IBM437").toString()
+            return LuaValue.valueOf(s)
+        }
+    }
+
+    private class FileClassReadAll(val path: Path) : ZeroArgFunction() {
+        override fun call() : LuaValue {
+            return FileClassReadAllBytes(path).call()
+        }
+    }
+
+    /** returns NO line separator! */
+    private class FileClassReadLine(val fr: FileReader) : ZeroArgFunction() {
+        val scanner = Scanner(fr.readText()) // no closing; keep the scanner status persistent
+
+        override fun call() : LuaValue {
+            return if (scanner.hasNextLine()) LuaValue.valueOf(scanner.nextLine())
+                   else LuaValue.NIL
+        }
+    }
+}

src/net/torvald/terrarum/virtualcomputer/luaapi/FilesystemTEVD.kt

@@ -0,0 +1,513 @@
+package net.torvald.terrarum.virtualcomputer.luaapi
+
+import org.luaj.vm2.*
+import org.luaj.vm2.lib.OneArgFunction
+import org.luaj.vm2.lib.TwoArgFunction
+import org.luaj.vm2.lib.ZeroArgFunction
+import net.torvald.terrarum.virtualcomputer.tvd.VDUtil.VDPath
+import net.torvald.terrarum.virtualcomputer.computer.TerrarumComputer
+import net.torvald.terrarum.virtualcomputer.luaapi.Term.Companion.checkIBM437
+import net.torvald.terrarum.virtualcomputer.tvd.VDUtil
+import net.torvald.terrarum.virtualcomputer.tvd.*
+import net.torvald.terrarum.virtualcomputer.tvd.VDFileWriter
+import java.io.*
+import java.nio.charset.Charset
+import java.util.*
+
+/**
+ * computer directory:
+ * .../computers/
+ *      media/hda/  ->  .../computers/<uuid for the hda>/
+ * 
+ * Created by minjaesong on 16-09-17.
+ *
+ *
+ * NOTES:
+ *      Don't convert '\' to '/'! Rev-slash is used for escape character in sh, and we're sh-compatible!
+ *      Use .absoluteFile whenever possible; there's fuckin oddity! (http://bugs.java.com/bugdatabase/view_bug.do;:YfiG?bug_id=4483097)
+ */
+internal class Filesystem(globals: Globals, computer: TerrarumComputer) {
+
+    init {
+        // load things. WARNING: THIS IS MANUAL!
+        globals["fs"] = LuaValue.tableOf()
+        globals["fs"]["list"] = ListFiles(computer) // CC compliant
+        globals["fs"]["exists"] = FileExists(computer) // CC/OC compliant
+        globals["fs"]["isDir"] = IsDirectory(computer) // CC compliant
+        globals["fs"]["isFile"] = IsFile(computer)
+        globals["fs"]["isReadOnly"] = IsReadOnly(computer) // CC compliant
+        globals["fs"]["getSize"] = GetSize(computer) // CC compliant
+        globals["fs"]["mkdir"] = Mkdir(computer)
+        globals["fs"]["mv"] = Mv(computer)
+        globals["fs"]["cp"] = Cp(computer)
+        globals["fs"]["rm"] = Rm(computer)
+        globals["fs"]["concat"] = ConcatPath(computer) // OC compliant
+        globals["fs"]["open"] = OpenFile(computer) //CC compliant
+        globals["fs"]["parent"] = GetParentDir(computer)
+        // fs.dofile defined in BOOT
+        // fs.fetchText defined in ROMLIB
+    }
+
+    companion object {
+        val sysCharset = Charset.forName("CP437")
+
+        fun LuaValue.checkPath(): String {
+            if (this.checkIBM437().contains(Regex("""\.\.""")))
+                throw LuaError("'..' on path is not supported.")
+            return this.checkIBM437().validatePath()
+        }
+
+        // Worst-case: we're on Windows or using a FAT32 partition mounted in *nix.
+        // Note: we allow / as the path separator and expect all \s to be converted
+        // accordingly before the path is passed to the file system.
+        private val invalidChars = Regex("""[<>:"|?*\u0000-\u001F]""") // original OC uses Set(); we use regex
+
+        fun isValidFilename(name: String) = !name.contains(invalidChars)
+
+        fun String.validatePath() : String {
+            if (!isValidFilename(this)) {
+                throw IOException("path contains invalid characters")
+            }
+            return this
+        }
+
+        /**
+         * return value is there for chaining only.
+         */
+        fun VDPath.dropMount(): VDPath {
+            if (this.hierarchy.size >= 2 && this[0].toCanonicalString() == "media") {
+                this.hierarchy.removeAt(0) // drop "media"
+                this.hierarchy.removeAt(0) // drop whatever mount symbol
+            }
+            return this
+        }
+
+        /**
+         * if path is {media, someUUID, subpath}, redirects to
+         * computer.diskRack[SOMEUUID]->subpath
+         * else, computer.diskRack["hda"]->subpath
+         */
+        fun TerrarumComputer.getFile(path: VDPath) : DiskEntry? {
+            val disk = this.getTargetDisk(path)
+
+            if (disk == null) return null
+
+            path.dropMount()
+
+            return VDUtil.getFile(disk, path)?.file
+        }
+
+        /**
+         * if path is like {media, fd1, subpath}, return
+         * computer.diskRack["fd1"]
+         * else, computer.diskRack[<boot device>]
+         */
+        fun TerrarumComputer.getTargetDisk(path: VDPath) : VirtualDisk? {
+            if (path.hierarchy.size >= 2 &&
+                    Arrays.equals(path[0], "media".toEntryName(DiskEntry.NAME_LENGTH, sysCharset))) {
+                val diskName = path[1].toCanonicalString()
+                val disk = this.diskRack[diskName]
+
+                return disk
+            }
+            else {
+                return this.diskRack[this.computerValue.getAsString("boot")]
+            }
+        }
+
+        fun TerrarumComputer.getDirectoryEntries(path: VDPath) : Array<DiskEntry>? {
+            val directory = this.getFile(path)
+
+            if (directory == null) return null
+            return VDUtil.getDirectoryEntries(this.getTargetDisk(path)!!, directory)
+        }
+
+        fun combinePath(base: String, local: String) : String {
+            return "$base$local".replace("//", "/")
+        }
+
+        private fun tryBool(action: (Unit) -> Unit): LuaValue {
+            try {
+                action(Unit)
+                return LuaValue.valueOf(true)
+            }
+            catch (gottaCatchemAll: Exception) {
+                return LuaValue.valueOf(false)
+            }
+        }
+    } // end of Companion Object
+
+    /**
+     * @param cname == UUID of the drive
+     *
+     * actual directory: <appdata>/Saves/<savename>/computers/<drivename>/
+     */
+    class ListFiles(val computer: TerrarumComputer) : OneArgFunction() {
+        override fun call(path: LuaValue) : LuaValue {
+            val path = VDPath(path.checkPath(), sysCharset)
+
+            val table = LuaTable()
+            try {
+                val directoryContents = computer.getDirectoryEntries(path)!!
+                directoryContents.forEachIndexed { index, diskEntry ->
+                    table.insert(index + 1, LuaValue.valueOf(diskEntry.filename.toCanonicalString()))
+                }
+            }
+            catch (e: KotlinNullPointerException) {}
+            return table
+        }
+    }
+
+    class FileExists(val computer: TerrarumComputer) : OneArgFunction() {
+        override fun call(path: LuaValue) : LuaValue {
+            val path = VDPath(path.checkPath(), sysCharset)
+            val disk = computer.getTargetDisk(path)
+
+            if (disk == null) return LuaValue.valueOf(false)
+
+            return LuaValue.valueOf(
+                    VDUtil.getFile(disk, path.dropMount()) != null
+            )
+        }
+    }
+
+    class IsDirectory(val computer: TerrarumComputer) : OneArgFunction() {
+        override fun call(path: LuaValue) : LuaValue {
+            val path = VDPath(path.checkPath(), sysCharset)
+            return LuaValue.valueOf(computer.getFile(path)?.contents is EntryDirectory)
+        }
+    }
+
+    class IsFile(val computer: TerrarumComputer) : OneArgFunction() {
+        override fun call(path: LuaValue) : LuaValue {
+            val path = VDPath(path.checkPath(), sysCharset)
+            return LuaValue.valueOf(computer.getFile(path)?.contents is EntryFile)
+        }
+    }
+
+    class IsReadOnly(val computer: TerrarumComputer) : OneArgFunction() {
+        override fun call(path: LuaValue) : LuaValue {
+            return LuaValue.valueOf(false)
+        }
+    }
+
+    /** we have 2 GB file size limit */
+    class GetSize(val computer: TerrarumComputer) : OneArgFunction() {
+        override fun call(path: LuaValue) : LuaValue {
+            val path = VDPath(path.checkPath(), sysCharset)
+            val file = computer.getFile(path)
+            try {
+                if (file!!.contents is EntryFile)
+                    return LuaValue.valueOf(file.contents.getSizePure())
+                else if (file.contents is EntryDirectory)
+                    return LuaValue.valueOf(file.contents.entries.size)
+            }
+            catch (e: KotlinNullPointerException) {
+            }
+
+            return LuaValue.NONE
+        }
+    }
+
+    // TODO class GetFreeSpace
+
+    /**
+     * returns true on success
+     */
+    class Mkdir(val computer: TerrarumComputer) : OneArgFunction() {
+        override fun call(path: LuaValue) : LuaValue {
+            return tryBool {
+                val path = VDPath(path.checkPath(), sysCharset)
+                val disk = computer.getTargetDisk(path)!!
+
+                VDUtil.addDir(disk, path.getParent(), path.last())
+            }
+        }
+    }
+
+    /**
+     * moves a directory, overwrites the target
+     */
+    class Mv(val computer: TerrarumComputer) : TwoArgFunction() {
+        override fun call(from: LuaValue, to: LuaValue) : LuaValue {
+            return tryBool {
+                val pathFrom = VDPath(from.checkPath(), sysCharset)
+                val disk1 = computer.getTargetDisk(pathFrom)
+                val pathTo = VDPath(to.checkPath(), sysCharset)
+                val disk2 = computer.getTargetDisk(pathTo)
+
+                VDUtil.moveFile(disk1!!, pathFrom, disk2!!, pathTo)
+            }
+        }
+    }
+
+    /**
+     * copies a directory, overwrites the target
+     * difference with ComputerCraft: it returns boolean, true on successful.
+     */
+    class Cp(val computer: TerrarumComputer) : TwoArgFunction() {
+        override fun call(from: LuaValue, to: LuaValue) : LuaValue {
+            return tryBool {
+                val pathFrom = VDPath(from.checkPath(), sysCharset)
+                val disk1 = computer.getTargetDisk(pathFrom)!!
+                val pathTo = VDPath(to.checkPath(), sysCharset)
+                val disk2 = computer.getTargetDisk(pathTo)!!
+
+                val oldFile = VDUtil.getFile(disk2, pathTo)
+
+                try {
+                    VDUtil.deleteFile(disk2, pathTo)
+                }
+                catch (e: FileNotFoundException) {
+                    "Nothing to delete beforehand"
+                }
+
+                val file = VDUtil.getFile(disk1, pathFrom)!!
+                try {
+                    VDUtil.addFile(disk2, pathTo.getParent(), file.file)
+                }
+                catch (e: FileNotFoundException) {
+                    // roll back delete on disk2
+                    if (oldFile != null) {
+                        VDUtil.addFile(disk2, oldFile.parent.entryID, oldFile.file)
+                        throw FileNotFoundException("No such destination")
+                    }
+                }
+            }
+        }
+    }
+
+    /**
+     * difference with ComputerCraft: it returns boolean, true on successful.
+     */
+    class Rm(val computer: TerrarumComputer) : OneArgFunction() {
+        override fun call(path: LuaValue) : LuaValue {
+            return tryBool {
+                val path = VDPath(path.checkPath(), sysCharset)
+                val disk = computer.getTargetDisk(path)!!
+
+                VDUtil.deleteFile(disk, path)
+            }
+        }
+    }
+
+    class ConcatPath(val computer: TerrarumComputer) : TwoArgFunction() {
+        override fun call(base: LuaValue, local: LuaValue) : LuaValue {
+            TODO()
+        }
+    }
+
+    /**
+     * @param mode: r, rb, w, wb, a, ab
+     *
+     * Difference: TEXT MODE assumes CP437 instead of UTF-8!
+     *
+     * When you have opened a file you must always close the file handle, or else data may not be saved.
+     *
+     * FILE class in CC:
+     * (when you look thru them using file = fs.open("./test", "w")
+     *
+     * file = {
+     *      close = function()
+     *      -- write mode
+     *      write = function(string)
+     *      flush = function() -- write, keep the handle
+     *      writeLine = function(string) -- text mode
+     *      -- read mode
+     *      readLine = function() -- text mode
+     *      readAll = function()
+     *      -- binary read mode
+     *      read = function() -- read single byte. return: number or nil
+     *      -- binary write mode
+     *      write = function(byte)
+     *      writeBytes = function(string as bytearray)
+     * }
+     */
+    class OpenFile(val computer: TerrarumComputer) : TwoArgFunction() {
+        override fun call(path: LuaValue, mode: LuaValue) : LuaValue {
+            val path = VDPath(path.checkPath(), sysCharset)
+            val disk = computer.getTargetDisk(path)!!
+
+            path.dropMount()
+
+            val mode = mode.checkIBM437().toLowerCase()
+            val luaClass = LuaTable()
+            val fileEntry = computer.getFile(path)!!
+
+            if (fileEntry.contents is EntryDirectory) {
+                throw LuaError("File '${fileEntry.getFilenameString(sysCharset)}' is directory.")
+            }
+
+            val file = fileEntry.contents as EntryFile
+
+            if (mode.contains(Regex("""[aw]""")))
+                throw LuaError("Cannot open file for " +
+                               "${if (mode.startsWith('w')) "read" else "append"} mode" +
+                               ": is readonly.")
+
+
+            when (mode) {
+                "r"  -> {
+                    try {
+                        val fr = StringReader(String(file.bytes, sysCharset))//FileReader(file)
+                        luaClass["close"] = FileClassClose(fr)
+                        luaClass["readLine"] = FileClassReadLine(fr)
+                        luaClass["readAll"] = FileClassReadAll(file)
+                    }
+                    catch (e: FileNotFoundException) {
+                        e.printStackTrace()
+                        throw LuaError(
+                                if (e.message != null && e.message!!.contains(Regex("""[Aa]ccess (is )?denied""")))
+                                    "$path: access denied."
+                                else
+                                    "$path: no such file."
+                        )
+                    }
+                }
+                "rb" -> {
+                    try {
+                        val fis = ByteArrayInputStream(file.bytes)
+                        luaClass["close"] = FileClassClose(fis)
+                        luaClass["read"] = FileClassReadByte(fis)
+                        luaClass["readAll"] = FileClassReadAll(file)
+                    }
+                    catch (e: FileNotFoundException) {
+                        e.printStackTrace()
+                        throw LuaError("$path: no such file.")
+                    }
+                }
+                "w", "a"  -> {
+                    try {
+                        val fw = VDFileWriter(fileEntry, mode.startsWith('a'), sysCharset)
+                        luaClass["close"] = FileClassClose(fw)
+                        luaClass["write"] = FileClassPrintText(fw)
+                        luaClass["writeLine"] = FileClassPrintlnText(fw)
+                        luaClass["flush"] = FileClassFlush(fw)
+                    }
+                    catch (e: FileNotFoundException) {
+                        e.printStackTrace()
+                        throw LuaError("$path: is a directory.")
+                    }
+                }
+                "wb", "ab" -> {
+                    try {
+                        val fos = VDFileOutputStream(fileEntry, mode.startsWith('a'), sysCharset)
+                        luaClass["close"] = FileClassClose(fos)
+                        luaClass["write"] = FileClassWriteByte(fos)
+                        luaClass["writeBytes"] = FileClassWriteBytes(fos)
+                        luaClass["flush"] = FileClassFlush(fos)
+                    }
+                    catch (e: FileNotFoundException) {
+                        e.printStackTrace()
+                        throw LuaError("$path: is a directory.")
+                    }
+                }
+            }
+
+            return luaClass
+        }
+    }
+
+    class GetParentDir(val computer: TerrarumComputer) : OneArgFunction() {
+        override fun call(path: LuaValue) : LuaValue {
+            val path = VDPath(path.checkPath(), sysCharset).getParent()
+            return LuaValue.valueOf(path.toString())
+        }
+    }
+
+
+    //////////////////////////////
+    // OpenFile implementations //
+    //////////////////////////////
+
+    private class FileClassClose(val fo: Closeable) : ZeroArgFunction() {
+        override fun call() : LuaValue {
+            fo.close()
+            return LuaValue.NONE
+        }
+    }
+
+    private class FileClassWriteByte(val fos: VDFileOutputStream) : OneArgFunction() {
+        override fun call(byte: LuaValue) : LuaValue {
+            fos.write(byte.checkint())
+
+            return LuaValue.NONE
+        }
+    }
+
+    private class FileClassWriteBytes(val fos: VDFileOutputStream) : OneArgFunction() {
+        override fun call(byteString: LuaValue) : LuaValue {
+            val byteString = byteString.checkIBM437()
+            val bytearr = ByteArray(byteString.length, { byteString[it].toByte() })
+            fos.write(bytearr)
+
+            return LuaValue.NONE
+        }
+    }
+
+    private class FileClassPrintText(val fw: VDFileWriter) : OneArgFunction() {
+        override fun call(string: LuaValue) : LuaValue {
+            val text = string.checkIBM437()
+            fw.write(text)
+            return LuaValue.NONE
+        }
+    }
+
+    private class FileClassPrintlnText(val fw: VDFileWriter) : OneArgFunction() {
+        override fun call(string: LuaValue) : LuaValue {
+            val text = string.checkIBM437() + "\n"
+            fw.write(text)
+            return LuaValue.NONE
+        }
+    }
+
+    private class FileClassFlush(val fo: Flushable) : ZeroArgFunction() {
+        override fun call() : LuaValue {
+            fo.flush()
+            return LuaValue.NONE
+        }
+    }
+
+    private class FileClassReadByte(val fis: ByteArrayInputStream) : ZeroArgFunction() {
+        override fun call() : LuaValue {
+            val readByte = fis.read()
+            return if (readByte == -1) LuaValue.NIL else LuaValue.valueOf(readByte)
+        }
+    }
+
+    private class FileClassReadAllBytes(val file: EntryFile) : ZeroArgFunction() {
+        override fun call() : LuaValue {
+            return LuaValue.valueOf(String(file.bytes, sysCharset))
+        }
+    }
+
+    private class FileClassReadAll(val file: EntryFile) : ZeroArgFunction() {
+        override fun call() : LuaValue {
+            return LuaValue.valueOf(String(file.bytes, sysCharset))
+        }
+    }
+
+    /** returns NO line separator! */
+    private class FileClassReadLine(fr: Reader) : ZeroArgFunction() {
+        val scanner = Scanner(fr.readText()) // no closing; keep the scanner status persistent
+
+        override fun call() : LuaValue {
+            return if (scanner.hasNextLine()) LuaValue.valueOf(scanner.nextLine())
+                   else LuaValue.NIL
+        }
+    }
+}
+
+/**
+ * drops appended NULs and return resulting ByteArray as String
+ */
+private fun ByteArray.toCanonicalString(): String {
+    var lastIndexOfRealStr = 0
+    for (i in this.lastIndex downTo 0) {
+        if (this[i] != 0.toByte()) {
+            lastIndexOfRealStr = i
+            break
+        }
+    }
+    return String(this.sliceArray(0..lastIndexOfRealStr))
+}

src/net/torvald/terrarum/virtualcomputer/luaapi/Term.kt

@@ -54,8 +54,9 @@ internal class Term(globals: Globals, term: Teletype) {
     companion object {
         fun LuaValue.checkIBM437(): String {
             if (this is LuaString)
-                return m_bytes.copyOfRange(m_offset, m_length).toString(Charset.forName("ISO-8859-1"))
+                return m_bytes.copyOfRange(m_offset, m_offset + m_length).toString(Charset.forName("CP437"))
                 // it only works if Charset is ISO-8859, despite of the name "IBM437"
+                // --> then would "CP437" work? -- Torvald at 2017-04-05
             else
                 throw LuaError("bad argument (string expected, got ${this.typename()})")
         }

src/net/torvald/terrarum/virtualcomputer/tvd/VDUtil.kt

@@ -0,0 +1,816 @@
+package net.torvald.terrarum.virtualcomputer.tvd
+
+import java.io.*
+import java.nio.charset.Charset
+import java.util.*
+import java.util.logging.Level
+import javax.naming.OperationNotSupportedException
+import kotlin.collections.ArrayList
+
+/**
+ * Created by SKYHi14 on 2017-04-01.
+ */
+object VDUtil {
+    class VDPath() {
+        /**
+         * input: (root)->etc->boot in Constructor
+         * output: ByteArrayListOf(
+         *      e t c \0 \0 \0 \0 \0 ... ,
+         *      b o o t \0 \0 \0 \0 ...
+         * )
+         *
+         * input: "/"
+         * interpretation: (root)
+         * output: ByteArrayListOf(
+         * )
+         */
+        var hierarchy = ArrayList<ByteArray>()
+
+        val lastIndex: Int
+            get() = hierarchy.lastIndex
+        fun last(): ByteArray = hierarchy.last()
+
+        constructor(strPath: String, charset: Charset) : this() {
+            val unsanitisedHierarchy = ArrayList<String>()
+            strPath.sanitisePath().split('/').forEach { unsanitisedHierarchy.add(it) }
+
+            // deal with bad slashes (will drop '' and tail '')
+            // "/bin/boot/drivers/" -> "bin/boot/drivers"
+            //  removes head slash
+            if (unsanitisedHierarchy[0].isEmpty())
+                unsanitisedHierarchy.removeAt(0)
+            //  removes tail slash
+            if (unsanitisedHierarchy.size > 0 &&
+                    unsanitisedHierarchy[unsanitisedHierarchy.lastIndex].isEmpty())
+                unsanitisedHierarchy.removeAt(unsanitisedHierarchy.lastIndex)
+
+            unsanitisedHierarchy.forEach {
+                hierarchy.add(it.toEntryName(DiskEntry.NAME_LENGTH, charset))
+            }
+        }
+
+        private constructor(newHierarchy: ArrayList<ByteArray>) : this() {
+            hierarchy = newHierarchy
+        }
+
+        override fun toString(): String {
+            val sb = StringBuilder()
+            if (hierarchy.size > 0) {
+                sb.append(hierarchy[0].toCanonicalString())
+            }
+            if (hierarchy.size > 1) {
+                (1..hierarchy.lastIndex).forEach {
+                    sb.append('/')
+                    sb.append(hierarchy[it].toCanonicalString())
+                }
+            }
+
+            return sb.toString()
+        }
+
+        operator fun get(i: Int) = hierarchy[i]
+        fun forEach(action: (ByteArray) -> Unit) = hierarchy.forEach(action)
+        fun forEachIndexed(action: (Int, ByteArray) -> Unit) = hierarchy.forEachIndexed(action)
+
+        fun getParent(ancestorCount: Int = 1): VDPath {
+            val newPath = ArrayList<ByteArray>()
+            hierarchy.forEach { newPath.add(it) }
+
+            repeat(ancestorCount) { newPath.removeAt(newPath.lastIndex) }
+            return VDPath(newPath)
+        }
+    }
+
+    fun dumpToRealMachine(disk: VirtualDisk, outfile: File) {
+        if (!outfile.exists()) outfile.createNewFile()
+        outfile.writeBytes(disk.serialize().array)
+    }
+
+    /**
+     * Reads serialised binary and returns corresponding VirtualDisk instance.
+     *
+     * @param crcWarnLevel Level.OFF -- no warning, Level.WARNING -- print out warning, Level.SEVERE -- throw error
+     */
+    fun readDiskArchive(infile: File, crcWarnLevel: Level = Level.SEVERE, warningFunc: ((String) -> Unit)? = null, charset: Charset): VirtualDisk {
+        val inbytes = infile.readBytes()
+
+        if (magicMismatch(VirtualDisk.MAGIC, inbytes))
+            throw RuntimeException("Invalid Virtual Disk file!")
+
+        val diskSize = inbytes.sliceArray(4..7).toIntBig()
+        val diskName = inbytes.sliceArray(8..8 + 31)
+        val diskCRC = inbytes.sliceArray(8 + 32..8 + 32 + 3).toIntBig() // to check with completed vdisk
+
+        val vdisk = VirtualDisk(diskSize, diskName)
+
+        //println("[VDUtil] currentUnixtime = $currentUnixtime")
+
+        var entryOffset = 44
+        while (!Arrays.equals(inbytes.sliceArray(entryOffset..entryOffset + 3), VirtualDisk.FOOTER_START_MARK)) {
+            //println("[VDUtil] entryOffset = $entryOffset")
+            // read and prepare all the shits
+            val entryIndexNum = inbytes.sliceArray(entryOffset..entryOffset + 3).toIntBig()
+            val entryTypeFlag = inbytes[entryOffset + 4]
+            val entryFileName = inbytes.sliceArray(entryOffset + 5..entryOffset + 260)
+            val entryCreationTime = inbytes.sliceArray(entryOffset + 261..entryOffset + 268).toLongBig()
+            val entryModifyTime = inbytes.sliceArray(entryOffset + 269..entryOffset + 276).toLongBig()
+            val entryCRC = inbytes.sliceArray(entryOffset + 277..entryOffset + 280).toIntBig() // to check with completed entry
+
+            val entryData = when (entryTypeFlag) {
+                DiskEntry.NORMAL_FILE -> {
+                    val filesize = inbytes.sliceArray(entryOffset + 281..entryOffset + 284).toIntBig()
+                    //println("[VDUtil] --> is file; filesize = $filesize")
+                    inbytes.sliceArray(entryOffset + 285..entryOffset + 284 + filesize)
+                }
+                DiskEntry.DIRECTORY   -> {
+                    val entryCount = inbytes.sliceArray(entryOffset + 281..entryOffset + 282).toShortBig()
+                    //println("[VDUtil] --> is directory; entryCount = $entryCount")
+                    inbytes.sliceArray(entryOffset + 283..entryOffset + 282 + entryCount * 4)
+                }
+                DiskEntry.SYMLINK     -> {
+                    inbytes.sliceArray(entryOffset + 281..entryOffset + 284)
+                }
+                else -> throw RuntimeException("Unknown entry with type $entryTypeFlag")
+            }
+
+
+
+            // update entryOffset so that we can fetch next entry in the binary
+            entryOffset += 281 + entryData.size + when (entryTypeFlag) {
+                DiskEntry.NORMAL_FILE -> 4
+                DiskEntry.DIRECTORY   -> 2
+                DiskEntry.SYMLINK     -> 0
+                else -> throw RuntimeException("Unknown entry with type $entryTypeFlag")
+            }
+
+
+            // create entry
+            val diskEntry = DiskEntry(
+                    entryID = entryIndexNum,
+                    filename = entryFileName,
+                    creationDate = entryCreationTime,
+                    modificationDate = entryModifyTime,
+                    contents = if (entryTypeFlag == DiskEntry.NORMAL_FILE) {
+                        EntryFile(entryData)
+                    }
+                    else if (entryTypeFlag == DiskEntry.DIRECTORY) {
+                        val entryList = ArrayList<EntryID>()
+                        (0..entryData.size / 4 - 1).forEach {
+                            entryList.add(entryData.sliceArray(4 * it..4 * it + 3).toIntBig())
+                        }
+
+                        EntryDirectory(entryList)
+                    }
+                    else if (entryTypeFlag == DiskEntry.SYMLINK) {
+                        EntrySymlink(entryData.toIntBig())
+                    }
+                    else
+                        throw RuntimeException("Unknown entry with type $entryTypeFlag")
+            )
+
+            // check CRC of entry
+            if (crcWarnLevel == Level.SEVERE || crcWarnLevel == Level.WARNING) {
+                val calculatedCRC = diskEntry.hashCode()
+
+                val crcMsg = "CRC failed: expected ${entryCRC.toHex()}, got ${calculatedCRC.toHex()}\n" +
+                             "at file \"${diskEntry.getFilenameString(charset)}\" (entry ID ${diskEntry.entryID})"
+
+                if (calculatedCRC != entryCRC) {
+                    if (crcWarnLevel == Level.SEVERE)
+                        throw IOException(crcMsg)
+                    else if (warningFunc != null)
+                        warningFunc(crcMsg)
+                }
+            }
+
+            // add entry to disk
+            vdisk.entries[entryIndexNum] = diskEntry
+        }
+
+
+        // check CRC of disk
+        if (crcWarnLevel == Level.SEVERE || crcWarnLevel == Level.WARNING) {
+            val calculatedCRC = vdisk.hashCode()
+
+            val crcMsg = "Disk CRC failed: expected ${diskCRC.toHex()}, got ${calculatedCRC.toHex()}"
+
+            if (calculatedCRC != diskCRC) {
+                if (crcWarnLevel == Level.SEVERE)
+                    throw IOException(crcMsg)
+                else if (warningFunc != null)
+                    warningFunc(crcMsg)
+            }
+        }
+
+        return vdisk
+    }
+
+
+    /**
+     * Get list of entries of directory.
+     */
+    fun getDirectoryEntries(disk: VirtualDisk, entry: DiskEntry): Array<DiskEntry> {
+        if (entry.contents !is EntryDirectory)
+            throw IllegalArgumentException("The entry is not directory")
+
+        val entriesList = ArrayList<DiskEntry>()
+        entry.contents.entries.forEach {
+            val entry = disk.entries[it]
+            if (entry != null) entriesList.add(entry)
+        }
+
+        return entriesList.toTypedArray()
+    }
+    /**
+     * Get list of entries of directory.
+     */
+    fun getDirectoryEntries(disk: VirtualDisk, entryID: EntryID): Array<DiskEntry> {
+        val entry = disk.entries[entryID]
+        if (entry == null) {
+            throw IOException("Entry does not exist")
+        }
+        else {
+            return getDirectoryEntries(disk, entry)
+        }
+    }
+
+    /**
+     * Search a entry using path
+     * @return Pair of <The file, Parent file>, or null if not found
+     */
+    fun getFile(disk: VirtualDisk, path: VDPath): EntrySearchResult? {
+        val searchHierarchy = ArrayList<DiskEntry>()
+        fun getCurrentEntry(): DiskEntry = searchHierarchy.last()
+        //var currentDirectory = disk.root
+
+        searchHierarchy.add(disk.entries[0]!!)
+
+        // path of root
+        if (path.hierarchy.size == 0) {
+            return EntrySearchResult(
+                    disk.entries[0]!!,
+                    disk.entries[0]!!
+            )
+        }
+
+        try {
+            // search for the file
+            path.forEachIndexed { i, nameToSearch ->
+                // if we hit the last elem, we won't search more
+                if (i <= path.lastIndex) {
+                    val currentDirEntries = getDirectoryEntries(disk, getCurrentEntry())
+
+                    var fileFound: DiskEntry? = null
+                    for (entry in currentDirEntries) {
+                        if (Arrays.equals(entry.filename, nameToSearch)) {
+                            fileFound = entry
+                            break
+                        }
+                    }
+                    if (fileFound == null) { // file not found
+                        throw KotlinNullPointerException()
+                    }
+                    else { // file found
+                        searchHierarchy.add(fileFound)
+                    }
+                }
+            }
+        }
+        catch (e1: KotlinNullPointerException) {
+            return null
+        }
+
+        // file found
+        return EntrySearchResult(
+                searchHierarchy[searchHierarchy.lastIndex],
+                searchHierarchy[searchHierarchy.lastIndex - 1]
+        )
+    }
+
+    /**
+     * SYNOPSIS  disk.getFile("bin/msh.lua")!!.file.getAsNormalFile(disk)
+     *
+     * Use VirtualDisk.getAsNormalFile(path)
+     */
+    private fun DiskEntry.getAsNormalFile(disk: VirtualDisk): EntryFile =
+            this.contents as? EntryFile ?:
+            if (this.contents is EntryDirectory)
+                throw RuntimeException("this is directory")
+            else if (this.contents is EntrySymlink)
+                disk.entries[this.contents.target]!!.getAsNormalFile(disk)
+            else
+                throw RuntimeException("Unknown entry type")
+    /**
+     * SYNOPSIS  disk.getFile("bin/msh.lua")!!.first.getAsNormalFile(disk)
+     *
+     * Use VirtualDisk.getAsNormalFile(path)
+     */
+    private fun DiskEntry.getAsDirectory(disk: VirtualDisk): EntryDirectory =
+            this.contents as? EntryDirectory ?:
+            if (this.contents is EntrySymlink)
+                disk.entries[this.contents.target]!!.getAsDirectory(disk)
+            else if (this.contents is EntryFile)
+                throw RuntimeException("this is not directory")
+            else
+                throw RuntimeException("Unknown entry type")
+
+    /**
+     * Search for the file and returns a instance of normal file.
+     */
+    fun getAsNormalFile(disk: VirtualDisk, path: VDPath) =
+            getFile(disk, path)!!.file.getAsNormalFile(disk)
+    /**
+     * Fetch the file and returns a instance of normal file.
+     */
+    fun getAsNormalFile(disk: VirtualDisk, entryIndex: EntryID) =
+            disk.entries[entryIndex]!!.getAsNormalFile(disk)
+    /**
+     * Search for the file and returns a instance of directory.
+     */
+    fun getAsDirectory(disk: VirtualDisk, path: VDPath) =
+            getFile(disk, path)!!.file.getAsDirectory(disk)
+    /**
+     * Fetch the file and returns a instance of directory.
+     */
+    fun getAsDirectory(disk: VirtualDisk, entryIndex: EntryID) =
+            disk.entries[entryIndex]!!.getAsDirectory(disk)
+    /**
+     * Deletes file on the disk safely.
+     */
+    fun deleteFile(disk: VirtualDisk, path: VDPath) {
+        disk.checkReadOnly()
+
+        val fileSearchResult = getFile(disk, path)!!
+
+        return deleteFile(disk, fileSearchResult.parent.entryID, fileSearchResult.file.entryID)
+    }
+    /**
+     * Deletes file on the disk safely.
+     */
+    fun deleteFile(disk: VirtualDisk, parentID: EntryID, targetID: EntryID) {
+        disk.checkReadOnly()
+
+        val file = disk.entries[targetID]
+        val parentDir = disk.entries[parentID]
+
+        fun rollback() {
+            if (!disk.entries.contains(targetID)) {
+                disk.entries[targetID] = file!!
+            }
+            if (!(parentDir!!.contents as EntryDirectory).entries.contains(targetID)) {
+                (parentDir.contents as EntryDirectory).entries.add(targetID)
+            }
+        }
+
+        if (parentDir == null || parentDir.contents !is EntryDirectory) {
+            throw FileNotFoundException("No such parent directory")
+        }
+        else if (file == null || !directoryContains(disk, parentID, targetID)) {
+            throw FileNotFoundException("No such file to delete")
+        }
+        else if (targetID == 0) {
+            throw IOException("Cannot delete root file system")
+        }
+        else if (file.contents is EntryDirectory && file.contents.entries.size > 0) {
+            throw IOException("Cannot delete directory that contains something")
+        }
+        else {
+            try {
+                // delete file record
+                disk.entries.remove(targetID)
+                // unlist file from parent directly
+                (disk.entries[parentID]!!.contents as EntryDirectory).entries.remove(targetID)
+            }
+            catch (e: Exception) {
+                rollback()
+                throw InternalError("Unknown error *sigh* It's annoying, I know.")
+            }
+        }
+    }
+    /**
+     * Changes the name of the entry.
+     */
+    fun renameFile(disk: VirtualDisk, path: VDPath, newName: String, charset: Charset) {
+        val file = getFile(disk, path)?.file
+
+        if (file != null) {
+            file.filename = newName.sanitisePath().toEntryName(DiskEntry.NAME_LENGTH, charset)
+        }
+        else {
+            throw FileNotFoundException()
+        }
+    }
+    /**
+     * Changes the name of the entry.
+     */
+    fun renameFile(disk: VirtualDisk, fileID: EntryID, newName: String, charset: Charset) {
+        val file = disk.entries[fileID]
+
+        if (file != null) {
+            file.filename = newName.sanitisePath().toEntryName(DiskEntry.NAME_LENGTH, charset)
+        }
+        else {
+            throw FileNotFoundException()
+        }
+    }
+    /**
+     * Add file to the specified directory.
+     */
+    fun addFile(disk: VirtualDisk, parentPath: VDPath, file: DiskEntry) {
+        disk.checkReadOnly()
+        disk.checkCapacity(file.serialisedSize)
+
+        try {
+            // add record to the directory
+            getAsDirectory(disk, parentPath).entries.add(file.entryID)
+            // add entry on the disk
+            disk.entries[file.entryID] = file
+        }
+        catch (e: KotlinNullPointerException) {
+            throw FileNotFoundException("No such directory")
+        }
+    }
+    /**
+     * Add file to the specified directory.
+     */
+    fun addFile(disk: VirtualDisk, directoryID: EntryID, file: DiskEntry) {
+        disk.checkReadOnly()
+        disk.checkCapacity(file.serialisedSize)
+
+        try {
+            // add record to the directory
+            getAsDirectory(disk, directoryID).entries.add(file.entryID)
+            // add entry on the disk
+            disk.entries[file.entryID] = file
+        }
+        catch (e: KotlinNullPointerException) {
+            throw FileNotFoundException("No such directory")
+        }
+    }
+    /**
+     * Add subdirectory to the specified directory.
+     */
+    fun addDir(disk: VirtualDisk, parentPath: VDPath, name: ByteArray) {
+        disk.checkReadOnly()
+        disk.checkCapacity(EntryDirectory.NEW_ENTRY_SIZE)
+
+        val newID = disk.generateUniqueID()
+
+        try {
+            // add record to the directory
+            getAsDirectory(disk, parentPath).entries.add(newID)
+            // add entry on the disk
+            disk.entries[newID] = DiskEntry(
+                    newID,
+                    name,
+                    currentUnixtime,
+                    currentUnixtime,
+                    EntryDirectory()
+            )
+        }
+        catch (e: KotlinNullPointerException) {
+            throw FileNotFoundException("No such directory")
+        }
+    }
+    /**
+     * Add file to the specified directory.
+     */
+    fun addDir(disk: VirtualDisk, directoryID: EntryID, name: ByteArray) {
+        disk.checkReadOnly()
+        disk.checkCapacity(EntryDirectory.NEW_ENTRY_SIZE)
+
+        val newID = disk.generateUniqueID()
+
+        try {
+            // add record to the directory
+            getAsDirectory(disk, directoryID).entries.add(newID)
+            // add entry on the disk
+            disk.entries[newID] = DiskEntry(
+                    newID,
+                    name,
+                    currentUnixtime,
+                    currentUnixtime,
+                    EntryDirectory()
+            )
+        }
+        catch (e: KotlinNullPointerException) {
+            throw FileNotFoundException("No such directory")
+        }
+    }
+
+
+    /**
+     * Imports external file and returns corresponding DiskEntry.
+     */
+    fun importFile(file: File, id: EntryID): DiskEntry {
+        if (file.isDirectory) {
+            throw IOException("The file is a directory")
+        }
+
+        return DiskEntry(
+                entryID = id,
+                filename = file.name.toByteArray(),
+                creationDate = currentUnixtime,
+                modificationDate = currentUnixtime,
+                contents = EntryFile(file.readBytes())
+        )
+    }
+    /**
+     * Export file on the virtual disk into real disk.
+     */
+    fun exportFile(entryFile: EntryFile, outfile: File) {
+        outfile.createNewFile()
+        outfile.writeBytes(entryFile.bytes)
+    }
+
+    /**
+     * Check for name collision in specified directory.
+     */
+    fun nameExists(disk: VirtualDisk, name: String, directoryID: EntryID, charset: Charset): Boolean {
+        return nameExists(disk, name.toEntryName(256, charset), directoryID)
+    }
+    /**
+     * Check for name collision in specified directory.
+     */
+    fun nameExists(disk: VirtualDisk, name: ByteArray, directoryID: EntryID): Boolean {
+        val directoryContents = getDirectoryEntries(disk, directoryID)
+        directoryContents.forEach {
+            if (Arrays.equals(name, it.filename))
+                return true
+        }
+        return false
+    }
+
+    /**
+     * Move file from to there, overwrite
+     */
+    fun moveFile(disk1: VirtualDisk, fromPath: VDPath, disk2: VirtualDisk, toPath: VDPath) {
+        val file = getFile(disk1, fromPath)
+
+        if (file != null) {
+            if (file.file.contents is EntryDirectory) {
+                throw IOException("Cannot move directory")
+            }
+
+            disk2.checkCapacity(file.file.contents.getSizeEntry())
+
+            try {
+                deleteFile(disk2, toPath)
+            }
+            catch (e: KotlinNullPointerException) { "Nothing to delete beforehand" }
+
+            deleteFile(disk1, fromPath) // any uncaught no_from_file will be caught here
+            try {
+                addFile(disk2, toPath.getParent(), file.file)
+            }
+            catch (e: FileNotFoundException) {
+                // roll back delete on disk1
+                addFile(disk1, file.parent.entryID, file.file)
+                throw FileNotFoundException("No such destination")
+            }
+        }
+        else {
+            throw FileNotFoundException("No such file to move")
+        }
+    }
+
+
+    /**
+     * Creates new disk with given name and capacity
+     */
+    fun createNewDisk(diskSize: Int, diskName: String, charset: Charset): VirtualDisk {
+        val newdisk = VirtualDisk(diskSize, diskName.toEntryName(VirtualDisk.NAME_LENGTH, charset))
+        val rootDir = DiskEntry(
+                entryID = 0,
+                filename = DiskEntry.ROOTNAME.toByteArray(charset),
+                creationDate = currentUnixtime,
+                modificationDate = currentUnixtime,
+                contents = EntryDirectory()
+        )
+
+        newdisk.entries[0] = rootDir
+
+        return newdisk
+    }
+    /**
+     * Creates new zero-filled file with given name and size
+     */
+    fun createNewBlankFile(disk: VirtualDisk, directoryID: EntryID, fileSize: Int, filename: String, charset: Charset) {
+        disk.checkReadOnly()
+        disk.checkCapacity(fileSize + DiskEntry.HEADER_SIZE + 4)
+
+        addFile(disk, directoryID, DiskEntry(
+                disk.generateUniqueID(),
+                filename.toEntryName(DiskEntry.NAME_LENGTH, charset = charset),
+                currentUnixtime,
+                currentUnixtime,
+                EntryFile(fileSize)
+        ))
+    }
+
+
+    /**
+     * Throws an exception if the disk is read-only
+     */
+    fun VirtualDisk.checkReadOnly() {
+        if (this.isReadOnly)
+            throw IOException("Disk is read-only")
+    }
+    /**
+     * Throws an exception if specified size cannot fit into the disk
+     */
+    fun VirtualDisk.checkCapacity(newSize: Int) {
+        if (this.usedBytes + newSize > this.capacity)
+            throw IOException("Not enough space on the disk")
+    }
+    fun ByteArray.toIntBig(): Int {
+        if (this.size != 4)
+            throw OperationNotSupportedException("ByteArray is not Int")
+
+        var i = 0
+        this.forEachIndexed { index, byte -> i += byte.toUint().shl(24 - index * 8)}
+        return i
+    }
+    fun ByteArray.toLongBig(): Long {
+        if (this.size != 8)
+            throw OperationNotSupportedException("ByteArray is not Long")
+
+        var i = 0L
+        this.forEachIndexed { index, byte -> i += byte.toUint().shl(56 - index * 8)}
+        return i
+    }
+    fun ByteArray.toShortBig(): Short {
+        if (this.size != 2)
+            throw OperationNotSupportedException("ByteArray is not Long")
+
+        return (this[0].toUint().shl(256) + this[1].toUint()).toShort()
+    }
+    fun String.sanitisePath(): String {
+        val invalidChars = Regex("""[<>:"|?*\u0000-\u001F]""")
+        if (this.contains(invalidChars))
+            throw IOException("path contains invalid characters")
+
+        val path1 = this.replace('\\', '/')
+        return path1
+    }
+    data class EntrySearchResult(val file: DiskEntry, val parent: DiskEntry)
+
+    fun resolveIfSymlink(disk: VirtualDisk, indexNumber: EntryID, recurse: Boolean = false): DiskEntry {
+        var entry: DiskEntry? = disk.entries[indexNumber]
+        if (entry == null) throw IOException("File does not exist")
+        if (entry.contents !is EntrySymlink) return entry
+        if (recurse) {
+            while (entry!!.contents is EntrySymlink) {
+                entry = disk.entries[(entry.contents as EntrySymlink).target]
+                if (entry == null) break
+            }
+        }
+        else {
+            entry = disk.entries[(entry.contents as EntrySymlink).target]
+        }
+        if (entry == null) throw IOException("Pointing file does not exist")
+        return entry
+    }
+
+    val currentUnixtime: Long
+        get() = System.currentTimeMillis() / 1000
+
+    fun directoryContains(disk: VirtualDisk, dirID: EntryID, targetID: EntryID): Boolean {
+        val dir = resolveIfSymlink(disk, dirID)
+
+        if (dir.contents !is EntryDirectory) {
+            throw FileNotFoundException("Not a directory")
+        }
+        else {
+            return dir.contents.entries.contains(targetID)
+        }
+    }
+}
+
+fun Byte.toUint() = java.lang.Byte.toUnsignedInt(this)
+fun magicMismatch(magic: ByteArray, array: ByteArray): Boolean {
+    return !Arrays.equals(array.sliceArray(0..magic.lastIndex), magic)
+}
+fun String.toEntryName(length: Int, charset: Charset): ByteArray {
+    val buffer = AppendableByteBuffer(length)
+    val stringByteArray = this.toByteArray(charset)
+    buffer.put(stringByteArray.sliceArray(0..minOf(length, stringByteArray.size) - 1))
+    return buffer.array
+}
+fun ByteArray.toCanonicalString(): String {
+    var lastIndexOfRealStr = 0
+    for (i in this.lastIndex downTo 0) {
+        if (this[i] != 0.toByte()) {
+            lastIndexOfRealStr = i
+            break
+        }
+    }
+    return String(this.sliceArray(0..lastIndexOfRealStr))
+}
+
+/**
+ * Writes String to the file
+ *
+ * @param fileEntry must be File, resolve symlink beforehand
+ * @param mode "w" or "a"
+ */
+class VDFileWriter(private val fileEntry: DiskEntry, private val append: Boolean, val charset: Charset) : Writer() {
+
+    private @Volatile var newFileBuffer = ArrayList<Byte>()
+
+    private @Volatile var closed = false
+
+    init {
+        if (fileEntry.contents !is EntryFile) {
+            throw FileNotFoundException("Not a file")
+        }
+    }
+
+    override fun write(cbuf: CharArray, off: Int, len: Int) {
+        if (!closed) {
+            val newByteArray = String(cbuf).toByteArray(charset)
+            newFileBuffer.addAll(newByteArray.asIterable())
+        }
+        else {
+            throw IOException()
+        }
+    }
+
+    override fun flush() {
+        if (!closed) {
+            val newByteArray = newFileBuffer.toByteArray()
+
+            if (!append) {
+                (fileEntry.contents as EntryFile).bytes = newByteArray
+            }
+            else {
+                val oldByteArray = (fileEntry.contents as EntryFile).bytes.copyOf()
+                val newFileBuffer = ByteArray(oldByteArray.size + newByteArray.size)
+
+                System.arraycopy(oldByteArray, 0, newFileBuffer, 0, oldByteArray.size)
+                System.arraycopy(newByteArray, 0, newFileBuffer, oldByteArray.size, newByteArray.size)
+
+                (fileEntry.contents as EntryFile).bytes = newByteArray
+            }
+
+            newFileBuffer = ArrayList<Byte>()
+
+            fileEntry.modificationDate = VDUtil.currentUnixtime
+        }
+        else {
+            throw IOException()
+        }
+    }
+
+    override fun close() {
+        flush()
+        closed = true
+    }
+}
+
+class VDFileOutputStream(private val fileEntry: DiskEntry, private val append: Boolean, val charset: Charset) : OutputStream() {
+
+    private @Volatile var newFileBuffer = ArrayList<Byte>()
+
+    private @Volatile var closed = false
+
+    override fun write(b: Int) {
+        if (!closed) {
+            newFileBuffer.add(b.toByte())
+        }
+        else {
+            throw IOException()
+        }
+    }
+
+    override fun flush() {
+        if (!closed) {
+            val newByteArray = newFileBuffer.toByteArray()
+
+            if (!append) {
+                (fileEntry.contents as EntryFile).bytes = newByteArray
+            }
+            else {
+                val oldByteArray = (fileEntry.contents as EntryFile).bytes.copyOf()
+                val newFileBuffer = ByteArray(oldByteArray.size + newByteArray.size)
+
+                System.arraycopy(oldByteArray, 0, newFileBuffer, 0, oldByteArray.size)
+                System.arraycopy(newByteArray, 0, newFileBuffer, oldByteArray.size, newByteArray.size)
+
+                (fileEntry.contents as EntryFile).bytes = newByteArray
+            }
+
+            newFileBuffer = ArrayList<Byte>()
+
+            fileEntry.modificationDate = VDUtil.currentUnixtime
+        }
+        else {
+            throw IOException()
+        }
+    }
+
+    override fun close() {
+        flush()
+        closed = true
+    }
+}

src/net/torvald/terrarum/virtualcomputer/tvd/VirtualDisk.kt

@@ -0,0 +1,246 @@
+package net.torvald.terrarum.virtualcomputer.tvd
+
+import java.nio.charset.Charset
+import java.util.*
+import java.util.function.Consumer
+import java.util.zip.CRC32
+
+/**
+ * Created by SKYHi14 on 2017-03-31.
+ */
+
+typealias EntryID = Int
+
+class VirtualDisk(
+        /** capacity of 0 makes the disk read-only */
+        var capacity: Int,
+        var diskName: ByteArray = ByteArray(NAME_LENGTH)
+) {
+    val entries = HashMap<EntryID, DiskEntry>()
+    val isReadOnly: Boolean
+        get() = capacity == 0
+    fun getDiskNameString(charset: Charset) = String(diskName, charset)
+    val root: DiskEntry
+        get() = entries[0]!!
+
+
+    private fun serializeEntriesOnly(): ByteArray {
+        val bufferList = ArrayList<Byte>()
+        entries.forEach {
+            val serialised = it.value.serialize()
+            serialised.forEach { bufferList.add(it) }
+        }
+
+        return ByteArray(bufferList.size, { bufferList[it] })
+    }
+
+    fun serialize(): AppendableByteBuffer {
+        val entriesBuffer = serializeEntriesOnly()
+        val buffer = AppendableByteBuffer(HEADER_SIZE + entriesBuffer.size + FOOTER_SIZE)
+        val crc = hashCode().toBigEndian()
+
+        buffer.put(MAGIC)
+        buffer.put(capacity.toBigEndian())
+        buffer.put(diskName.forceSize(NAME_LENGTH))
+        buffer.put(crc)
+        buffer.put(entriesBuffer)
+        buffer.put(FOOTER_START_MARK)
+        buffer.put(EOF_MARK)
+
+        return buffer
+    }
+
+    override fun hashCode(): Int {
+        val crcList = IntArray(entries.size)
+        var crcListAppendCursor = 0
+        entries.forEach { t, u ->
+            crcList[crcListAppendCursor] = u.hashCode()
+            crcListAppendCursor++
+        }
+        crcList.sort()
+        val crc = CRC32()
+        crcList.forEach { crc.update(it) }
+
+        return crc.value.toInt()
+    }
+
+    /** Expected size of the virtual disk */
+    val usedBytes: Int
+        get() = entries.map { it.value.serialisedSize }.sum() + HEADER_SIZE + FOOTER_SIZE
+
+    fun generateUniqueID(): Int {
+        var id: Int
+        do {
+            id = Random().nextInt()
+        } while (null != entries[id] || id == FOOTER_MARKER)
+        return id
+    }
+
+    override fun equals(other: Any?) = if (other == null) false else this.hashCode() == other.hashCode()
+    override fun toString() = "VirtualDisk(name: ${getDiskNameString(Charsets.UTF_8)}, capacity: $capacity bytes, crc: ${hashCode().toHex()})"
+
+    companion object {
+        val HEADER_SIZE = 44 // according to the spec
+        val FOOTER_SIZE = 6  // footer mark + EOF
+        val NAME_LENGTH = 32
+
+        val MAGIC = "TEVd".toByteArray()
+        val FOOTER_MARKER = 0xFEFEFEFE.toInt()
+        val FOOTER_START_MARK = FOOTER_MARKER.toBigEndian()
+        val EOF_MARK = byteArrayOf(0xFF.toByte(), 0x19.toByte())
+    }
+}
+
+
+class DiskEntry(
+        // header
+        var entryID: EntryID,
+        var filename: ByteArray = ByteArray(NAME_LENGTH),
+        var creationDate: Long,
+        var modificationDate: Long,
+
+        // content
+        val contents: DiskEntryContent
+) {
+    fun getFilenameString(charset: Charset) = if (entryID == 0) ROOTNAME else String(filename, charset)
+
+    val serialisedSize: Int
+        get() = contents.getSizeEntry() + HEADER_SIZE
+
+    companion object {
+        val HEADER_SIZE = 281 // according to the spec
+        val ROOTNAME = "(root)"
+        val NAME_LENGTH  = 256
+
+        val NORMAL_FILE = 1.toByte()
+        val DIRECTORY =   2.toByte()
+        val SYMLINK =     3.toByte()
+        private fun DiskEntryContent.getTypeFlag() =
+                if      (this is EntryFile)      NORMAL_FILE
+                else if (this is EntryDirectory) DIRECTORY
+                else if (this is EntrySymlink)   SYMLINK
+                else 0 // NULL
+
+        fun getTypeString(entry: DiskEntryContent) = when(entry.getTypeFlag()) {
+            NORMAL_FILE -> "File"
+            DIRECTORY   -> "Directory"
+            SYMLINK     -> "Symbolic Link"
+            else        -> "(unknown type)"
+        }
+    }
+
+    fun serialize(): AppendableByteBuffer {
+        val serialisedContents = contents.serialize()
+        val buffer = AppendableByteBuffer(281 + serialisedContents.size)
+
+        buffer.put(entryID.toBigEndian())
+        buffer.put(contents.getTypeFlag())
+        buffer.put(filename.forceSize(NAME_LENGTH))
+        buffer.put(creationDate.toBigEndian())
+        buffer.put(modificationDate.toBigEndian())
+        buffer.put(this.hashCode().toBigEndian())
+        buffer.put(serialisedContents.array)
+
+        return buffer
+    }
+
+    override fun hashCode() = contents.serialize().getCRC32()
+
+    override fun equals(other: Any?) = if (other == null) false else this.hashCode() == other.hashCode()
+
+    override fun toString() = "DiskEntry(name: ${getFilenameString(Charsets.UTF_8)}, index: $entryID, type: ${contents.getTypeFlag()}, crc: ${hashCode().toHex()})"
+}
+
+
+fun ByteArray.forceSize(size: Int): ByteArray {
+    return ByteArray(size, { if (it < this.size) this[it] else 0.toByte() })
+}
+interface DiskEntryContent {
+    fun serialize(): AppendableByteBuffer
+    fun getSizePure(): Int
+    fun getSizeEntry(): Int
+}
+class EntryFile(var bytes: ByteArray) : DiskEntryContent {
+
+    override fun getSizePure() = bytes.size
+    override fun getSizeEntry() = getSizePure() + 4
+
+    /** Create new blank file */
+    constructor(size: Int): this(ByteArray(size))
+
+    override fun serialize(): AppendableByteBuffer {
+        val buffer = AppendableByteBuffer(getSizeEntry())
+        buffer.put(getSizePure().toBigEndian())
+        buffer.put(bytes)
+        return buffer
+    }
+}
+class EntryDirectory(val entries: ArrayList<EntryID> = ArrayList<EntryID>()) : DiskEntryContent {
+
+    override fun getSizePure() = entries.size * 4
+    override fun getSizeEntry() = getSizePure() + 2
+
+    override fun serialize(): AppendableByteBuffer {
+        val buffer = AppendableByteBuffer(getSizeEntry())
+        buffer.put(entries.size.toShort().toBigEndian())
+        entries.forEach { indexNumber -> buffer.put(indexNumber.toBigEndian()) }
+        return buffer
+    }
+
+    companion object {
+        val NEW_ENTRY_SIZE = DiskEntry.HEADER_SIZE + 4
+    }
+}
+class EntrySymlink(val target: EntryID) : DiskEntryContent {
+
+    override fun getSizePure() = 4
+    override fun getSizeEntry() = 4
+
+    override fun serialize(): AppendableByteBuffer {
+        val buffer = AppendableByteBuffer(4)
+        return buffer.put(target.toBigEndian())
+    }
+}
+
+
+fun Int.toHex() = this.toLong().and(0xFFFFFFFF).toString(16).padStart(8, '0').toUpperCase()
+fun Int.toBigEndian(): ByteArray {
+    return ByteArray(4, { this.ushr(24 - (8 * it)).toByte() })
+}
+fun Long.toBigEndian(): ByteArray {
+    return ByteArray(8, { this.ushr(56 - (8 * it)).toByte() })
+
+}
+fun Short.toBigEndian(): ByteArray {
+    return byteArrayOf(
+            this.div(256).toByte(),
+            this.toByte()
+    )
+}
+fun AppendableByteBuffer.getCRC32(): Int {
+    val crc = CRC32()
+    crc.update(this.array)
+    return crc.value.toInt()
+}
+class AppendableByteBuffer(val size: Int) {
+    val array = ByteArray(size, { 0.toByte() })
+    private var offset = 0
+
+    fun put(byteArray: ByteArray): AppendableByteBuffer {
+        System.arraycopy(
+                byteArray, // source
+                0,         // source pos
+                array,     // destination
+                offset,    // destination pos
+                byteArray.size // length
+        )
+        offset += byteArray.size
+        return this
+    }
+    fun put(byte: Byte): AppendableByteBuffer {
+        array[offset] = byte
+        offset += 1
+        return this
+    }
+    fun forEach(consumer: (Byte) -> Unit) = array.forEach(consumer)
+}